To be quite honest in the instance of Cora and Rumple neither of them really loved each other enough to choose the other over power. I don't think either of them hurt each other.

the look on his face... Heartbreaking. He really thought she wanted him the way he was... He was willing to share his power with her, to make her his lover, apprentice & wife.

Both heartbreaking. Cora just was another blow in a wounded, bleeding heart.

"We saw him as pre-Dark One with Milah but they had very few moments of happiness but Cora is his soulmate in a lot of ways. She understands him in a way that other people don’t because she’s not trying to make him a better man." - Eddy Kitsis quote from TV Fanatic

Again: also a Rumbelle fan. But can't deny how catchy this dark romance is.

Only because Milah came first. She didn't even want him when he was a "good" person. The first cut is the deepest, and she's the one that started this whole ball rolling in the first place.

Cora was honest with him, brutally honest yes but she didn't lead him on or make him feel that it was his fault. Despite her faults she did right by Rumple. She loved him more then Milah ever did.

Milah went with hook, because she thought Rumple was a coward. Cora didn't leave for another man or thought that he was a coward.

Cora humilliated him, Millah hurt him to his very core.

At least he knew Cora had loved him.

In my opinion, she's the reason why he became the Dark One. She so heartlessly humiliated him
Cora had truly loved him, didn't leave him for another man, never saw him as a coward

100%. Milah left his son along with Rumpel.....What's more tragic and wrong than that?

Because he had a son with her, and he was able to love more back then.